In recent years, with remarkable improvement of computers or computer systems including display devices, it is required to make large an image display screen and display a plurality of images at the same time as functions required for such computers or computer systems.
For example, in a CAD or CAM device, since a machine assembling diagram to be described occupies a wide area, it is necessary to use a display device having a high resolution and a large image display screen.
However, since a display device, having high resolution, which has been generally utilized, has a size of 23 inches in the largest size, there is a case that whole of the machine assembling diagram and the like cannot be displayed on one screen surface. As a result, in such case, a mechanical designer operates the device to display such a machine assembling diagram merely by partially displaying a part thereof and then modifies or amends it, thus being troublesome for the designer.
Furthermore, in a computer utilized for an office work, there is a case that a document is prepared with reference to a preliminarily prepared list or list table. In such case, for example, the screen of the display device is divided into two sections so that the above-mentioned list table is displayed on one divided screen section, and then, a document is prepared on the other divided screen section by starting up and driving a word processor software. In the case of utilizing this device, however, the display screen of the display device is divided into two sections, so that the respective screen sections have small areas, and for example, there may cause a case that the list table cannot be entirely displayed, leading to failure of smoothly preparing the document, which is a new problem.
Incidentally, it is conventional technology to arrange a plurality of display devices or units side by side to thereby display one image by whole of them or a plurality of images individually. In such arrangement of the display devices, the respective display devices, each supported by a support stand, are merely arranged on a desk horizontally or vertically, or the respective display devices, which are supported by arms, are arranged horizontally or vertically.
However, these arrangements provide the following problems. That is, in each arrangement, since the individual display device has an outer frame having a wide width, a large distance is present between the screens of the adjacent display devices, and accordingly, as the screen size becomes large, it is difficult for a viewer to clearly observe the screen.
In addition, it is required to prepare the support stands or supporting arms of the numbers same as the numbers of the display devices, requiring much space for arrangement. Especially, in the case of using the supporting arms, it is further required to locate a support member such as stand or wall to which the arms are secured, leading to an enlargement of the equipment, involving much cost, and troublesome working will be needed for transferring these arms, members and devices.
Still furthermore, in a certain case, according to an image to be displayed, a display device having a vertically large screen may be usable more than a display device having a horizontally large screen as conventional. In such case, in the conventional technology, the screen of the display device is rotated by 90 degrees, which requires an additional device or equipment to rotate the screen and a specific software therefore, involving additional cost.